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Original paper
Scalp acupuncture effects of stroke studied with
magnetic resonance imaging: different actions in the
two stroke model rats
Isao Inoue,1 Mari Fukunaga,2 Keiko Koga,2 Hong-Du Wang,3 Makoto Ishikawa2
1
Institute for Enzyme Research,
Tokushima University,
Tokushima, Japan; 2 Tokushima
Research Institute, Otsuka
Pharmaceutical Co, Tokushima,
Japan; 3 TCM Department,
Luzhou Medical College, Luzhou,
Sichuan, PR China
Correspondence to:
Dr Isao Inoue, Institute for
Enzyme Research, Tokushima
University, Tokushima 770-8503,
Japan;
[email protected]
ABSTRACT
Background: Scalp acupuncture (SA) therapy on strokes
has been empirically established and widely used in
clinics in China. The evidence from clinical studies
suggests that SA produces significant benefits for some
patients with stroke.
Methods: The effect of scalp acupuncture was studied
using MRI for two different stroke models: spontaneously
hypertensive stroke-prone (SHR-SP) rats and rats with
transiently induced focal cerebral ischaemia by middle
cerebral artery occlusion for 2 h (MCAO rats).
Results: Stroke onset in SHR-SP rats was characterised
by a development of vasogenic oedema without any
appearance of cytotoxic oedema. Scalp acupuncture
reduced rapidly neurological dysfunction in SHR-SP rats
and reduced the volume of the vasogenic oedema during
the same period. In contrast, in MCAO rats, focal cerebral
ischaemia caused an immediate development of cytotoxic
oedema without any appearance of vasogenic oedema.
Vasogenic oedema developed after reperfusion. Scalp
acupuncture had no significant effects on the cytotoxic
oedema, vasogenic oedema or neurological dysfunction of
the MCAO rats within the time span examined.
Conclusion: Scalp acupuncture had a rapid and strong
effect on neurological dysfunction only in the hypertensive
stroke-model by reducing the vasogenic oedema. Our
results suggest that, if there are similar underlying
mechanisms in human strokes, scalp acupuncture may be
more beneficial for patients with strokes of hypertensioncaused vasogenic origin than ischaemic origin.
Scalp acupuncture (SA) is a therapy used to treat
neurological dysfunction by needling specific stimulation areas in the scalp. This therapy originated in
China from ‘‘Huangdi’s Internal Classic,’’ over
2000 years ago. However, its rapid development and
wide clinical use for therapy in strokes have occurred
only since the 1970s. In 1984, the China Association
of Acupuncture and Moxibustion standardised these
portions onto 14 lines, and these 14 lines have been
approved as an ‘‘International Standard of ScalpAcupuncture’’ at the WHO West Pacific Zone
Conference (Japan, 1984). It is now suggested from
statistical analyses of clinical results that the effects of
scalp acupuncture on strokes are significant. Evidence
from clinical studies suggests that SA produces
significant benefits for some patients with stroke,
with good results reported in 60–80% of patients.
Comparative studies have shown that the rate of
recovery in SA-treated patients with stroke was
approximately twice that in those treated with
medication alone.1–3 One remarkable effect of SA is
a rapid and phasic recovery from paralyses. The effect
Acupunct Med 2009;27:155–162. doi:10.1136/aim.2009.000430
appears in 60% of patients with stroke within 10–
30 min after an SA treatment, and during the phasic
period the muscle force in the paralytic side increases
by two grades or more.4–6 Although the mechanisms
are unknown at present, these clinical results strongly
suggest that the stimulation of SA is transmitted to
the brain and activates the inherent self-curing
function. In order to elucidate such effects of SA on
a scientific basis, it is important to reproduce the SA
therapy in experimental animals that provide reliable
controls and exclude psychological effects. A genetic
strain of rats, spontaneously hypertensive strokeprone (SHR-SP), is an animal model which develops
spontaneous onset of hypertensive strokes. In many
aspects, cerebrovascular pathology resembles the
human disease.7 8 Rats with surgery-induced focal
brain ischaemia by middle cerebral artery occlusion
(MCAO) have been used as an animal model of
ischaemic strokes.
MRI is one of the most powerful tools for the
detection of cerebrovascular abnormalities, especially for seeking the time-dependent changes in
abnormalities under non-invasive conditions.
Hence, MRI observations of the brain of SHR-SP
and that of MCAO rats have been made rather
extensively.9–17 Vasogenic oedema that occurs by an
increase in the water volume in the extracellular
space as a consequence of the impairment of the
blood–brain-barrier (BBB) can be detected by T2
imaging as increased values of the T2 relaxation
time. Cytotoxic oedema that occurs by swelling of
brain cells as the result of energy failure and loss of
ion homeostasis can be detected by apparent
diffusion coefficient (ADC) imaging as decreased
ADC values. Previous reports have shown that the
types of cerebrovascular abnormality associated
with the stroke onset are different between SHRSP and MCAO rats. The stroke onset in SHR-SP is
characterised by the appearance of vasogenic
oedema without any development of cytotoxic
oedema.12 In MCAO rats, the brain ischaemia
induces cytotoxic oedema but does not induce
vasogenic oedema in the early stage of ischaemia.16
We studied the effect of SA using MRI on the two
different stroke models: SHR-SP and MCAO rats with
transient focal ischaemia for 2 h. This report describes
the experimental results showing that SA showed
different effects between the two stroke models.
MATERIALS AND METHODS
Animals
This study was performed in accordance with the
Guidelines for Animal Care and Use in Otsuka
Pharmaceutical Co, 1 April 2004.
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Original paper
Forty male, 8-week-old SHR-SP rats were purchased from
Japan SLC Inc (Hamamatsu, Japan). They were kept in an
animal room at 22uC, lit for 12 h daily, fed dry foods for SHR-SP
(Funabashi Farm, Chiba, Japan) and given distilled water
containing 1% (w/v) NaCl. The NaCl water was given
throughout the experiments. The blood pressure was measured
by the tail-cuff method using an automatic sphygmomanometer (Softron, BP-98A, Tokyo). Rats that suffered a stroke
were alternatively separated into two groups: rats in one group
were treated with SA and the other used for control without SA
treatment.
Twenty-eight male, 9–10-week-old Sprague-Dawley rats
purchased from Japan SLC were used for MCAO. Rats were
kept in the animal room and fed pellet food (MF, Oriental
Yeast, Tokyo) and drinking tap water ad libitum. Rats were
anaesthetised with thiopental (42 mg/kg, intraperitoneal), and
placed on a heating pad to keep the body temperature at 38uC.
Focal cerebral ischaemia was induced by transient occlusion of
the left middle cerebral artery (MCA) as described.16 Briefly,
surgical nylon suture thread (3–0 in size) with a rounded tip
was advanced from the external carotid artery into the lumen of
the internal carotid artery to block the blood flow of MCA. Two
hours after MCAO, reperfusion was allowed by withdrawal of
the suture thread. Then, each rat immediately underwent MRI
observations. Only those rats in which the MCAO successfully
induced cytotoxic oedema in the brain were used for experiments.
Grade of paralyses
When SHR-SP rats suffered stroke spontaneously, the animals
became ‘‘dispirited,’’ the hair became fluffy and lost its lustre,
and paralyses appeared in limbs at different sites between rats.
Other dysfunction such as tics, hyperaemia in the eye and
incontinence appeared but not in all rats. We classified the
paralyses into five grades from observations of expressed
paralyses, modifying the examinations of Bederson et al.19
Table 1 shows the characteristic symptoms of paralyses at each
grade.
SA treatment
SA was treated for 10 min a day without anaesthesia by
alternatively changing the side of needle insertion. For SHR-SP
SA treatment was started when the stroke onset was observed,
and for MCAO rats after reperfusion. After sterilisation of the
skin, a stainless steel acupuncture needle (0.3 mm thick and
26 mm long) was inserted from the point of ‘‘Baihui’’ (GV20) to
the point that may correspond to ‘‘Qubin’’ (GB7) in the
opposite side of paretic limbs between the galea aponeurotica
and the periosteum along the cranial bone; electrical stimulation
was then applied for 10 min using a pulse generator (Nihon
Table 1 Characteristic symptoms of paralyses at each grade
Grade 0
Grade 1
Grade 2
Grade 3
Grade 4
156
Normal
Mild wrist and elbow flexion and adduction of a shoulder appear
Rats can walk normally, but slower than normal rats
Symptoms at Grade 1 become more pronounced with full flexion of
the wrist and the elbow, and adduction of the shoulder with internal
rotation
Rats can walk straight but are lame in the paretic limb
This grade is characterised as being a significant decrease in the
resistant strength against pushing toward the paretic side
Rats can walk, but not straight, and deviate toward the paretic side
Rats cannot walk; they circle toward the paretic side or cannot move
Kohden, SEN-710, Tokyo). One stimulation output was
connected to the needle, and the other to a hindlimb via a
piece of wet cotton. Pulses were given in sets, each pulse
consisting of a bipolar rectangular voltage pulse with 300 ms
duration. For electrical stimulation, the pulses at 2.5 Hz were
applied for 4 s at every 4 s interval. The pulse intensity was
increased gradually and fixed when both the hindlimb and an
ear near the needle tip were locally twitched while the pulses
were given; the voltage was 3–3.5 V.
MRI observations
For MRI measurements, rats were gas-anaesthetised with
isoflurane (1–2%) mixed with 30% O2 and 70% N2O, and
placed in a stereotaxic head holder. The rectal temperature was
feedback-controlled at 38uC by warm/cool water throughout
the MRI experiments. MRI observations were performed using
an Inova 300 Imaging System (7T) with VNMRj 1.1D software
(Varian, Palo Alto, California). A volume coil and a surface coil
(RAPID Biomedical, Rimpar, Germany) were used for signal
transmission and detection, respectively. The bregma position
was determined by the coronal images.
The T2 image was obtained by multislice spin echo sequence
using the following parameters: pulse repetition time (TR)
3000 ms; echo time (TE) 10, 30, 50, 70 and 90 ms; number of
scans (NT) 1. ADC image was obtained by multislice StejskalTanner type pulsed gradient spin echo sequence using the
following parameters: TR 1500 ms; TE 40 ms; time between the
rising edges of the two diffusion-encoding gradient (D) 22 ms;
duration of these gradients (d) 12 ms; b-factors = 35, 400, 700,
1000 and 1300 s/mm2; NT 2. The slice thickness for T2 and
ADC measurements for SHR-SP was 1 mm; the images of 13 or
15 slices were obtained. In T2 and ADC measurements for
MCAO rats, the slice thickness was 2 mm, and the images of
seven slices were obtained. For all T2 and ADC images, the
matrix size was 2566128, the images were zero-filled to
2566256, and the field of view was 40640 mm. The area of
vasogenic oedema in a T2 image of SHR-SP was calculated,
summing the number of pixels having T2 values greater than
50 ms, and that of the MCAO rat by summing the number of
pixels having a deviation more than mean ¡3SD from the mean
pixel values of the contralateral hemisphere. The area of
cytotoxic oedema in an ADC image was obtained from the
number of pixels with ADC values below 80% of each
contralateral value. The oedema volume in the brain was
calculated by summation of the oedema area of every slice
multiplied by the slice thickness.
Dynamic susceptibility contrast MRI was performed to assess
a relative cerebral blood volume (CBV) and a cerebral blood flow
(CBF). After the precontrast image acquiring, Magnevist
(Schering, Berlin), an MRI contrast agent, was administered
via the tail vein at a dose of 0.3 mmol/kg. A series of 49
gradient-echo single slice images with TR 7.8 ms, TE 3 ms and
flip angle 25u was acquired.17 Relative CBF and relative CBV
were determined with commercially available image analysis
software (MEDx, Version 3.43; Medical Numerics, Virginia) To
evaluate the leakage of contrast agent caused by impairment of
BBB permeability, a postcontrast image was acquired 10 min
after Magnevist administration. T1 weighted images for preand postcontrast images were acquired by a multislice spin echo
sequence with TR 500 ms, TE 12 ms and NT 2; the matrix size
was 2566256. The images were zero-filled to 5126512, and the
field of view was 25625 mm. Contrast MRI was obtained by
subtracting the precontrast images from the corresponding
postcontrast images.
Acupunct Med 2009;27:155–162. doi:10.1136/aim.2009.000430
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Original paper
Some rats were killed using ether after MRI observations for
histological examination. The brain was removed and cut into
2 mm thick coronal blocks. The brain slices were immersed in a
physiological saline (Otsuka Pharmaceutical, Tokushima, Japan)
containing 2% solution of 2,3,5-triphenyltetrazolium chloride
(TTC, Sigma-Aldrich, St Louis, Missouri) in the dark at room
temperature for 30 min and then fixed in 10% phosphatebuffered formalin at 4uC. TTC-stained brain slices were scanned
with a scanner (Color Imaging GT-8700, Seiko Epson, Suwa,
Japan).
Numerical values are expressed as mean (SD). The p value
was obtained by the Student t test, and p,0.05 was considered
statistically significant.
RESULTS
SA effects on paralyses in SHR-SP rats
The blood pressure of SHR-SP rats gradually increased after
switching the drinking-water to one containing 1% NaCl.
Thirty-six rats out of 40 suffered a stroke within 7 weeks after
NaCl loading. The systolic and the diastolic blood pressures on
the day of stroke onset measured for 24 rats were 264.9 (SD
26.4) mm Hg and 174.0 (16.3) mm Hg, respectively. SA
dramatically alleviated neurological dysfunction caused by a
stroke attack in SHR-SP rats. Figure 1 shows photographs of a
rat demonstrating such dramatic effects of SA and representative dysfunction at each grade of paralysis. This rat experienced
a severe stroke 27 days after being given NaCl water. Both foreand hindlimbs were paralysed; the grade of paralyses was 4 at
day 0 and day 1. At day 2, the grade decreased to 3, but it could
not lift the body. At day 3, it could walk but slowly, and the
grade was 2. At day 4, the paralyses were almost cured (grade 0),
and the rat could walk normally. This rat suffered a second
stroke 10 days after the first stroke onset and died after 12 days.
The average values of the grade 1–3 days after stroke onset (day
0) in the SA-treated group of rats and untreated group of rats
are summarised in table 2A. The paralysis grade in the SAtreated rats became lower, whereas that in the untreated rats
became higher during the study. The effect of SA became
statistically significant (p,0.05) on day 2. SA had no significant
effect on the blood pressure as previously repeported.18
Therefore, SA did not reduce the risk of stroke attack. The
SA-treated rats were repeatedly attacked by strokes, even after
the paralyses were mitigated by SA treatments, and they
eventually died. However, as a result of the powerful effect of
SA on the neurological dysfunction, the SA-treated group of rats
were able to survive much longer (21.7 (14.5) days; n = 11) than
the untreated group of rats (4.6 (3.7) days; n = 15) after the first
stroke onset.
SA effects on paralyses of MCAO rats
In MCAO rats, neurological dysfunction became apparent 1 day
after reperfusion. However, conspicuous paralysis appeared only
in a forelimb. The paralysis grade was 1–3 in most cases. SA had
no statistically significant effects on the paralysis in MCAO rats
during day 1 to day 3 (table 2B).
MRI observations in the brain after stroke onset
Figure 2A shows representative MRI images of the SHR-SP
brain demonstrating that the stroke onset is characterised by an
increase in the relaxation time measured with T2 images
(whitened area) and also the increase in the ADC values
measured with ADC images, indicating the appearance of
vasogenic oedema without cytotoxic oedema.12 (These images
can be interpreted as indicating that the interstitial space in the
brain parenchyma and the ventricles were filled with isoosmotic fluid and serum proteins that leaked out from the
bloodstream through impaired BBB, but it was not accompanied
by swelling of the brain cells that would be caused by an energy
Figure 1 Photographic pictures taken during 4 days after stroke onset demonstrating the scalp acupuncture effect on paralyses appearing in a rat
after suffering a stroke. Scalp acupuncture was treated for 10 min each day. The graph shows a plot of the grade of paralyses of this rat during the
5 days after the stroke onset.
Acupunct Med 2009;27:155–162. doi:10.1136/aim.2009.000430
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Table 2 Grades of paralyses in spontaneously hypertensive stroke-prone and middle cerebral artery
occlusion rats
A. Grade of paralyses in spontaneously hypertensive stroke-prone rats
Day 0
Scalp-acupuncture2.88 (0.85)
treated (n = 18) (SD)
Untreated (n = 15) (SD) 2.43 (1.07)
p Value
0.90
Day 1
Day 2
Day 3
2.47 (1.01)
1.88 (1.11)
1.70 (1.33)
2.62 (0.51)
0.64
2.92 (0.86)
0.0094
3.15 (0.80)
0.0049
Day 1
Day 2
Day 3
1.53 (1.00)
1.58 (1.30)
1.27 (1.19)
1.272 (0.63)
0.50
1.64 (1.20)
0.92
0.75 (0.62)
0.20
B. Grade of paralyses in middle cerebral artery occlusion rats
Day 0
Scalp-acupuncture1.00 (0.00)
treated (n = 12) (SD)
Untreated (n = 11) (SD) 1.00 (0.63)
p Value
1.00
failure of the cells.12) Leakage could be detected with the
contrast MIR image using Magnevist (fig 2B). The haemorrhage
appeared at the focus of the lesion area 2 days after the stroke
onset (the black spot in Right of the T2 image in fig 2B).
Figure 2C shows the perfusion images indicating that there was
no significant change in the cerebral blood flow (CBV) or the
cerebral blood volume (CBF), even though the hemisphere was
expanded by the vasogenic oedema.
In contrast to the cases of SHR-SP, the transient brain
ischaemia by MCAO induces cytotoxic oedema without
vasogenic oedema (fig 3A top). The cytotoxic oedema is
characterised by the decreased ADC values (darkened area),
reflecting the transfer of water from extracellular space into the
cells due to cellular energy failure. Both CBF and CBV decreased
remarkably during the MCAO (fig 3C). After reperfusion, the
volume of the cytotoxic oedema quickly decreased once, then
increased again and reached the maximum level at 24 h (fig 3A
left, B). On the other hand, vasogenic oedema appeared only
after reperfusion and increased to the maximum level at 24 h
(fig 3A right, B). The second phase of development of the
cytotoxic oedema and the appearance of the vasogenic oedema
were obviously not directly induced by the ischaemia. These
were induced by blood recirculation. Then, both the cytotoxic
oedema and the vasogenic oedema decreased gradually.
Effect of SA on the vasogenic oedema in SHR-SP
It was found that the volume of vasogenic oedema in SHR-SP
decreased markedly in a short time after SA treatment. Figure 4
Figure 2 MRI images of the brain of a
spontaneously hypertensive stroke-prone
rat. (A) T2 images (top) and apparent
diffusion coefficient (ADC) images
(bottom) of the same slice on the day of
stroke onset (left) and at 2 days after
stroke onset (right). (B) T2 images (top)
and contrast MRI images (bottom) of the
same slice on the day of stroke onset
(left) and at 2 days after stroke onset
(right) indicating the leakage from the
focus of the oedema. Haemorrhage
appeared at day 2 in the lesion area.
(C) T2 image (top), relative cerebral blood
flow (CBF) (middle) and relative cerebral
blood volume (CBV) (bottom) taken from
the same slice at 3 days after stroke
onset.
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Original paper
Figure 3 MRI images of the brain of middle cerebral artery occlusion (MCAO) rats. (A) Apparent diffusion coefficient (ADC) images (left) and T2
images (right) of two slices taken immediately after MCAO (top) and 2, 4, 8 and 24 h after reperfusion. (B) Time-dependent changes in the cytotoxic
oedema volume and the vasogenic oedema volume calculated from the whole sets of MRI images of A. (C) ADC image, cerebral blood flow (CBF) and
cerebral blood volume (CBV) taken from the same slice during MCAO.
shows T2 images of 15 slices on the day of stroke onset (left) and
those recorded a day after (right). On the day of stroke onset, the
vasogenic oedema increased in the left hemisphere (right side in
the T2 images), and the ventricles were filled with fluid. The grade
of paralyses was 4, the oedema volume in the brain parenchyma
was calculated to be 162 mm3, and the fluid volume in the
ventricles was 299 mm3. SA was treated for 10 min after the MRI
observations. A day after, the grade of paralyses decreased to 2.
The oedema volume decreased to 71 mm3 (44%), and the fluid in
the ventricles decreased to 125 mm3. This rat suffered second
attack on day 3, the paralyses grade increased to a level of 4, the
oedema volume increased to 179 mm3, and the fluid in the
ventricles increased to 282 mm3.
Figure 5 compares the grade of paralyses and the volume of
vasogenic oedema in three SA-treated SHR-SP. Vasogenic
oedema appeared in different areas, and the paralysis grade
was different between rats. However, the results clearly indicate
that there was a close relation between the pattern of changes
in grade of paralyses and that of the volume of vasogenic
oedema in each rat. In fact, in the SA-treated rats, the oedema
volume decreased to 47.9 (26.9)% (n = 7) during 24–48 h after
the stroke onset, but in the untreated rats the oedema volume
increased to 109.4 (43.1)% (n = 6), demonstrating the significant effect of SA (p = 0.0067). It should be noted that in one
untreated rat out of six, the volume of vasogenic oedema
decreased to 33% in 2 days, accompanied by a decrease in the
Acupunct Med 2009;27:155–162. doi:10.1136/aim.2009.000430
paralyses grade by 2. One such case of spontaneous reduction in
the oedema volume in SHR-SP was reported by Blezer et al.9
These results support the view that the brain possesses an
endogenous function of draining out excess water from the
interstitial space in the brain parenchyma and the ventricles.20
SA effects on the cytotoxic and the vasogenic oedema in MCAO
rats
In contrast to the strong effect of SA on the brain lesion in SHRSP, SA had no significant effect on either the time-dependent
change in the volume of cytotoxic oedema (fig 6 left) or that in
vasogenic oedema (fig 6 right) in MCAO rats.
Comparison of infarct between SHR-SP and MCAO rats
TTC staining that measures tissue viability has been used to
evaluate infarct size.21 Figure 7A shows T2 images and TTC
staining at nearly the same coronal section of the brain obtained
from the SA-treated SHR-SP (SP#7A) used in the experiment of
fig 5 (right). The TTC staining indicated that although small
spots around the foci of blood serum leakage and/or haemorrhage
underwent infarction during 4 days after the stroke onset, the
major portion of the brain in the vasogenic oedema seen on the
day of stroke onset (day 0) did not. In contrast, in the MCAO rat,
the greater portion of the brain in the cytotoxic oedema
underwent infarction 1 day after reperfusion (fig 7B).
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Figure 4 T2 images of whole 15 slices obtained from a spontaneously hypertensive stroke-prone rat, demonstrating the appearance of vasogenic
oedema at the onset of stroke (left) and a dramatic reduction in the vasogenic oedema in 1 day after scalp acupuncture (SA) treatment for 10 min
(right). The grade of paralyses decreased from 4 to 2 on 1 day, and the volume of vasogenic oedema from 162.0 mm3 to 71.3 mm3. The fluid volume in
the ventricles changed from 299 to 125 mm3 during the same period.
DISCUSSION
We have shown here that the causes of brain abnormalities in
SHR-SP rats are different from those in MCAO rats, and that
the effects of SA on neurological dysfunction are different
between the causes of strokes, that is hypertension and
ischaemia. The brain abnormality in SHR-SP has a hypertension-caused vasogenic origin, and the stroke onset is characterised by the expansion of vasogenic oedema due to leakage of
iso-osmotic serum into the interstitial space of the brain
parenchyma via BBB with increased permeability that occurs
without failure of cell metabolism (figs 2, 7A). SA has strong
and rapid effects in reducing oedema size and in mitigating
neurological dysfunction (figs 1, 4, 5). In contrast, in MCAO
rats, the focal brain ischaemia rapidly induces cytotoxic oedema
due to cell swelling by the cell energy failure but does not induce
vasogenic oedema in the early stage of ischaemia (fig 3). After
recirculation of blood, the oxygen supply quickly reduces the
cytotoxic oedema. At the same time, recirculation is known to
induce intense superoxide, nitric oxide and peroxynitrate synthesis.21 Overproduction of these radicals leads to reperfusioninduced cell injury.21 22 The delayed development of vasogenic
oedema occurs as a consequence of the BBB disruption.22 SA has
no significant effect on the vasogenic oedema that has occurred, or
the spontaneous decrease in the vasogenic or cytotoxic oedema in
the MCAO rats at least within the short time span examined
(fig 6), suggesting that SA is not effective for neurological
160
dysfunction caused by neuronal injury. This may account for the
different effects of SA between SHR-SP and MCAO rats.
However, it is true that in clinics, SA has been used to treat
patients in a chronic stage not only with haemorrhage strokes
but also with ischaemic strokes, and yielded better therapeutic
results than an SA-untreated group of patients.2 3 This suggests
that SA has multifarious effects over a short to long time span.
In fact, a number of studies on MCAO rats have shown that
acupuncture treatments including SA and body acupuncture
promote neuronal activity, neuroprotective effects, neurogenesis, etc with a longer timescale.23–27 The present study could
demonstrate only some of the SA effects, that is the rapid effect
on the neurological dysfunction in SHR-SP in relation to the
vasogenic oedema that is not accompanied by neuronal injury.
Vasogenic oedema fluid found in the white matter primarily
consisting of aligned axonal tracts is higher than that in the grey
matter consisting of tangles of neuronal cell processes.20 Because
the brain volume is limited by the skull, the generation of
vasogenic oedema in the white matter would compress the
neuronal tracts that consist of axons and surrounding glial
cells, and narrow the diffusion space between an axon and
surrounding glial cells, the so-called periaxonal space or
Frankenhaeuser and Hodgkin (F-H) space.28 If this occurs, K+
released from axons as the physical consequence of action
potential propagation would be accumulated in the F-H space. It
is well known that the action potential propagation fails when K+
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Figure 5 Changes in the grade of paralyses (top) and the volume of vasogenic oedema (bottom) obtained from three spontaneously hypertensive
stroke-prone rats treated with scalp acupuncture for 10 min per day, showing a close relationship between grade of paralyses and oedema volume. The
rats suffered a second stroke during the experiments. ‘‘MRI’’ means that MRI observations were made on the days indicated, and ‘‘TTC’’ (2,3,5triphenyltetrazolium chloride) means that a histological examination was performed by TTC staining after the MRI observation.
is accumulated in the F-H space.29 As the neurons are not injured
but simply lost the capability of propagating action potentials by
the K+ depolarisation, the propagation failure can be immediately
restored when the F-H space widens by the reduction in vasogenic
oedema. This may explain the rapid recovery from neurological
dysfunction when the vasogenic oedema was reduced.
It is not understood how SA can reduce so rapidly the
vasogenic oedema caused by hypertension. There may be two
possible mechanisms that can reduce vasogenic oedema. One is
the rapid recovery of microvascular integrity, and the other
enhancement of the endogenous potential in draining out the
excess water from the brain parenchyma into veins. Previous
Figure 6 Time-dependent changes in
the volumes of cytotoxic oedema (left)
and vasogenic oedema (right) in middle
cerebral artery occlusion rats of the scalp
acupuncture (SA) treated group (n = 7)
and the untreated group (n = 7), showing
that SA had no significant effect on the
spontaneous changes in the volume of the
oedema in this timescale of observations.
The error bars indicate the magnitude of
SD.
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Figure 7 Generation of infarction in a spontaneously hypertensive
stroke-prone (SHR-SP) rat (A) and middle cerebral artery occlusion
(MCAO) rat (B) measured with 2,3,5-triphenyltetrazolium chloride (TTC)
staining. (A) T2 images (T2) at day 0 and at day 4, and TTC staining
(TTC) at day 4 after stroke onset at nearly the same coronal section of
the brain obtained from the scalp-acupuncture-treated SHR-SP (SP#7A)
used in the experiment of fig 5 (right). (B) Apparent diffusion coefficient
(ADC) images (ADC) on day 0 and day 1, and TTC staining on day 1 after
reperfusion obtained from a MCAO rat in nearly the same coronal section
of the brain.
studies have shown that in SHR-SP, neurological symptoms
appear later than abnormalities in the arterial structures, such as
vessel wall alterations particularly with medial necrosis and
focal degeneration of the medial smooth muscle cells.30 Together
with the results shown in fig 7A, it is unlikely that these longperiod degenerations of arteries could be restored so quickly by
SA treatment. Therefore, it seems more likely that SA
stimulates the endogenous potential in maintaining the brain
water homeostasis.
In clinics, the effectiveness of SA is different between
patients, and the rapid effects are observed in 60% of
patients.4–7 If human stroke involves in part a similar mechanism to that which occurs in SHR-SP stroke, the present
experiments could explain the clinical results, and SA would
be more beneficial for patients with stroke with hypertensioncaused vasogenic origin.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
Acknowledgements: We thank Q Bone, Marine Biological Association of UK,
Plymouth, UK and ER Brown, Stazione Zoologica Anton Dohrn, Naples, Italy, for critical
reading of the manuscript. II was supported by the Japan Society for the Promotion of
Science (No 19650088), and H-DW by the Fujii-Otsuka Fund for International Education
and Research Exchanges.
28.
Competing interests: None.
30.
Provenance and peer review: Not commissioned; externally peer reviewed.
162
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Acupunct Med 2009;27:155–162. doi:10.1136/aim.2009.000430
Downloaded from http://aim.bmj.com/ on July 12, 2017 - Published by group.bmj.com
Scalp acupuncture effects of stroke studied
with magnetic resonance imaging: different
actions in the two stroke model rats
Isao Inoue, Mari Fukunaga, Keiko Koga, Hong-Du Wang and Makoto
Ishikawa
Acupunct Med 2009 27: 155-162
doi: 10.1136/aim.2009.000430
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